The differences between pluripotent and differentiated cells include stage specific chromatin structure and transcriptional hierarchy which are both regulated by and orchestrated with the epigenetic events. Such events include alterations in DNA methylation, histone modifications, polycomb gene group and noncoding RNA expression. In this lecture the overview will be given on chromatin dynamics and epigenetic modification status during neural stem cell development. Examples of regulatory machineries responsible for gene repression at each stage of neural stem cell development will be indicated. Neural stem cells are characterized by their ability to give rise to multiple neural lineages, including neurons, astrocytes, and oligodendrocytes. Previously we have obtained neural stem cells from human cord blood (HUCB-NSC) which has been investigated by our group for their ability to be reprogrammed or differentiated using combination of small molecules as epigenetic modulators. It was demonstrated that the influence of small chemicals: histone deacetylases (Trichostatin A -TSA) and methyltransferases (RG-108) on the expression of Oct4, Sox2, Rex1 and Nanog genes depended on developmental stages of HUCB-NSC. Incubation for 5 days in reprogramming conditions followed by short time culture (3 days) in ESCM (Embryonic Stem Cell Medium) on Matrigel resulted with only partial stimulation of the investigated pluripotency markers. Nevertheless, the differences in expression pattern between tested treatment conditions were observed. Cells grown under Serum Free culture conditions treated with a combination of epigenetic inhibitors as well as recombinant proteins after longer incubation in ESCM on Matrigel were able to gain full iPS morphology and showed continuous expression of pluripotent genes. None of the mentioned above factors were alone sufficient to reprogram NSC to stable pluripotency state. Additionally the mechanism of regulation DNMTs and HDACs genes (namely DNMT 3B and HDAC1) by methyltransferases and histone deacetylases inhibitors and their role in reprogramming and differentiation process of HUCB-NSC have been tested. The present study demonstated that small molecules such as TSA and RG108 together with reprogramming proteins in lowered oxygen conditions can change epigenetic status of cells and activate and sustain pluripotent state in HUCB-NSC. In conclusion it is evident that the developmental stage of the cells and epigenetic modulation play an important role in the induction of pluripotency genes expression. Sponsored by grant from Polish Ministry of Scientific Research and Higher Education Nr 5978/B/PO1/2010/38
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.